※ The main unit is for display purposes only; the product is the case itself. We've created a case with the perfect size and inner diameter for both the receiver and transmitter, allowing them to be stored in the smallest possible size without shaking. The external dimensions are: Width 54 x Depth 45 x Height 93mm. We received feedback that it could also be used for 20L, although we're not sure if it was a perfect fit. The lid snaps shut securely and is difficult to open unintentionally, but it opens with a click when pressed from the side. There's no chance of it falling open when turned upside down. Therefore, you can attach double-sided tape to the back of the lid and stick it directly to an effects case (^^). There's no corner interference during opening and closing, which is common with this type of product, and operation is very smooth. We had some concerns about leaving it directly on a surface during charging, so we've designed it so that you can plug in the charging cable while it's still stored in the case.